Electric storage system

Abstract

An electric storage system is provided including a switching unit which is arranged between an electric storage unit of an electric storage device which is configured to be connectable in parallel with another power supply device and wire which is configured to electrically connect the electric storage device and the another power supply device, wherein the switching unit is configured to switch the electrical connection relationship between the wire and the electric storage unit; and a restriction unit which is connected in parallel with the switching unit between the wire and the electric storage unit, has a higher resistance than the switching unit, and is configured to cause current to flow in a direction from the electric storage unit to the wire and suppress current flowing in a direction from the wire to the electric storage unit.

What is claimed is: 
     
       1. An electric storage system comprising:
 a switching unit which is arranged between an electric storage unit of an electric storage device which is configured to be connectable in parallel with another power supply device and wire which is configured to electrically connect the electric storage device and the another power supply device, wherein the switching unit is configured to switch an electrical connection relationship between the wire and the electric storage unit; 
 a restriction unit which is connected in parallel with the switching unit between the wire and the electric storage unit, has a higher resistance than the switching unit, and is configured to cause current to flow in a direction from the electric storage unit to the wire and suppress current flowing in a direction from the wire to the electric storage unit, 
 wherein the restriction unit includes: 
 a current amount restricting unit which is configured to restrict a current amount of current flowing through the restriction unit; and 
 a current direction restricting unit which is connected in series with the current amount restricting unit, and is configured to cause current to flow in a direction from the electric storage unit to the wire and prevent current from flowing in a direction from the wire to the electric storage unit, wherein the restriction unit further has a connecting unit which is connected in series with the current amount restricting unit and the current direction restricting unit, and which is configured to electrically connect the current amount restricting unit, the current direction restricting unit, and the electric storage unit to the wire; 
 a switching control unit which is configured to control the switching unit; and 
 a restriction control unit which is configured to control the restriction unit, wherein 
 the switching control unit is configured to control the switching unit such that (i) when a terminal voltage of the switching unit meets a predetermined condition, the switching unit electrically connects the wire and the electric storage unit, and (ii) when the terminal voltage of the switching unit does not meet the predetermined condition, the switching unit electrically disconnects the wire and the electric storage unit, and 
 the restriction control unit is configured to control the connecting unit such that when the switching unit electrically disconnects the wire and the electric storage unit, the connecting unit electrically connects the current amount restricting unit, the current direction restricting unit, and the electric storage unit to the wire. 
 
     
     
       2. The electric storage system according to  claim 1 , wherein the restriction control unit is configured to control the connecting unit such that after the switching unit electrically connects the wire and the electric storage unit, the connecting unit electrically disconnects the current amount restricting unit, the current direction restricting unit, and the electric storage unit from the wire. 
     
     
       3. The electric storage system according to  claim 1 , wherein the current direction restricting unit has a diode, and the diode is arranged such that a direction from the electric storage unit to the wire is a forward direction. 
     
     
       4. The electric storage system according to  claim 3 , wherein the current amount restricting unit further includes a fixed resistor connected in series with the diode. 
     
     
       5. The electric storage system according to  claim 1 , wherein the restriction unit is configured to be attachable and detachable to/from one end and an other end of the switching unit. 
     
     
       6. The electric storage system according to  claim 1 , wherein the electric storage device includes the switching unit and the restriction unit, and is configured to be attachable and detachable to/from the wire. 
     
     
       7. The electric storage system according to  claim 1 , further comprising a restriction control unit which is configured to control the restriction unit, wherein the restriction control unit is configured to control the connecting unit such that the connecting unit electrically connects the current amount restricting unit, the current direction restricting unit, and the electric storage unit to the wire when the electric storage system is physically or electrically connected to a load device outside the electric storage system or before the electric storage system is electrically connected to the load device outside the electric storage system. 
     
     
       8. The electric storage system according to  claim 7 , further comprising a switching control unit which is configured to control the switching unit, wherein the switching control unit is configured to control the switching unit such that the switching unit electrically disconnects the wire and the electric storage unit before the electric storage system is electrically connected to the load device outside the electric storage system. 
     
     
       9. The electric storage system according to  claim 3 , wherein the current amount restricting unit further includes a constant power load connected in series with the diode. 
     
     
       10. The electric storage system according to  claim 3 , wherein the current amount restricting unit further includes a constant current load connected in series with the diode.